jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp

Fri, 16 Mar 2012 16:14:04 +0100

author: nloodin
date: Fri, 16 Mar 2012 16:14:04 +0100
changeset 3665: 8a729074feae
parent 2314: f95d63e2154a
child 4037: da91efe96a93
permissions: -rw-r--r--

7154517: Build error in hotspot-gc without precompiled headers
Reviewed-by: jcoomes, brutisso

 /*
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
 #include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
 #include "gc_implementation/shared/gcPolicyCounters.hpp"
 #include "gc_interface/gcCause.hpp"
 #include "memory/collectorPolicy.hpp"
 #include "runtime/timer.hpp"
 #include "utilities/top.hpp"
 #include <math.h>
 PSAdaptiveSizePolicy::PSAdaptiveSizePolicy(size_t init_eden_size,
                                            size_t init_promo_size,
                                            size_t init_survivor_size,
                                            size_t intra_generation_alignment,
                                            double gc_pause_goal_sec,
                                            double gc_minor_pause_goal_sec,
                                            uint gc_cost_ratio) :
      AdaptiveSizePolicy(init_eden_size,
                         init_promo_size,
                         init_survivor_size,
                         gc_pause_goal_sec,
                         gc_cost_ratio),
      _collection_cost_margin_fraction(AdaptiveSizePolicyCollectionCostMargin/
 .0),
      _intra_generation_alignment(intra_generation_alignment),
      _live_at_last_full_gc(init_promo_size),
      _gc_minor_pause_goal_sec(gc_minor_pause_goal_sec),
      _latest_major_mutator_interval_seconds(0),
      _young_gen_change_for_major_pause_count(0)
 {
   // Sizing policy statistics
   _avg_major_pause    =
     new AdaptivePaddedAverage(AdaptiveTimeWeight, PausePadding);
   _avg_minor_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
   _avg_major_interval = new AdaptiveWeightedAverage(AdaptiveTimeWeight);
   _avg_base_footprint = new AdaptiveWeightedAverage(AdaptiveSizePolicyWeight);
   _major_pause_old_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _major_pause_young_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _major_collection_estimator =
     new LinearLeastSquareFit(AdaptiveSizePolicyWeight);
   _young_gen_size_increment_supplement = YoungGenerationSizeSupplement;
   _old_gen_size_increment_supplement = TenuredGenerationSizeSupplement;
   // Start the timers
   _major_timer.start();
   _old_gen_policy_is_ready = false;
 }
 void PSAdaptiveSizePolicy::major_collection_begin() {
   // Update the interval time
   _major_timer.stop();
   // Save most recent collection time
   _latest_major_mutator_interval_seconds = _major_timer.seconds();
   _major_timer.reset();
   _major_timer.start();
 }
 void PSAdaptiveSizePolicy::update_minor_pause_old_estimator(
     double minor_pause_in_ms) {
   double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
   _minor_pause_old_estimator->update(promo_size_in_mbytes,
     minor_pause_in_ms);
 }
 void PSAdaptiveSizePolicy::major_collection_end(size_t amount_live,
   GCCause::Cause gc_cause) {
   // Update the pause time.
   _major_timer.stop();
   if (gc_cause != GCCause::_java_lang_system_gc ||
       UseAdaptiveSizePolicyWithSystemGC) {
     double major_pause_in_seconds = _major_timer.seconds();
     double major_pause_in_ms = major_pause_in_seconds * MILLIUNITS;
     // Sample for performance counter
     _avg_major_pause->sample(major_pause_in_seconds);
     // Cost of collection (unit-less)
     double collection_cost = 0.0;
     if ((_latest_major_mutator_interval_seconds > 0.0) &&
         (major_pause_in_seconds > 0.0)) {
       double interval_in_seconds =
         _latest_major_mutator_interval_seconds + major_pause_in_seconds;
       collection_cost =
         major_pause_in_seconds / interval_in_seconds;
       avg_major_gc_cost()->sample(collection_cost);
       // Sample for performance counter
       _avg_major_interval->sample(interval_in_seconds);
     }
     // Calculate variables used to estimate pause time vs. gen sizes
     double eden_size_in_mbytes = ((double)_eden_size)/((double)M);
     double promo_size_in_mbytes = ((double)_promo_size)/((double)M);
     _major_pause_old_estimator->update(promo_size_in_mbytes,
       major_pause_in_ms);
     _major_pause_young_estimator->update(eden_size_in_mbytes,
       major_pause_in_ms);
     if (PrintAdaptiveSizePolicy && Verbose) {
       gclog_or_tty->print("psAdaptiveSizePolicy::major_collection_end: "
         "major gc cost: %f  average: %f", collection_cost,
         avg_major_gc_cost()->average());
       gclog_or_tty->print_cr("  major pause: %f major period %f",
         major_pause_in_ms,
         _latest_major_mutator_interval_seconds * MILLIUNITS);
     }
     // Calculate variable used to estimate collection cost vs. gen sizes
     assert(collection_cost >= 0.0, "Expected to be non-negative");
     _major_collection_estimator->update(promo_size_in_mbytes,
         collection_cost);
   }
   // Update the amount live at the end of a full GC
   _live_at_last_full_gc = amount_live;
   // The policy does not have enough data until at least some major collections
   // have been done.
   if (_avg_major_pause->count() >= AdaptiveSizePolicyReadyThreshold) {
     _old_gen_policy_is_ready = true;
   }
   // Interval times use this timer to measure the interval that
   // the mutator runs.  Reset after the GC pause has been measured.
   _major_timer.reset();
   _major_timer.start();
 }
 // If the remaining free space in the old generation is less that
 // that expected to be needed by the next collection, do a full
 // collection now.
 bool PSAdaptiveSizePolicy::should_full_GC(size_t old_free_in_bytes) {
   // A similar test is done in the scavenge's should_attempt_scavenge().  If
   // this is changed, decide if that test should also be changed.
   bool result = padded_average_promoted_in_bytes() > (float) old_free_in_bytes;
   if (PrintGCDetails && Verbose) {
     if (result) {
       gclog_or_tty->print("  full after scavenge: ");
     } else {
       gclog_or_tty->print("  no full after scavenge: ");
     }
     gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT
       " padded_average_promoted " SIZE_FORMAT
       " free in old gen " SIZE_FORMAT,
       (size_t) average_promoted_in_bytes(),
       (size_t) padded_average_promoted_in_bytes(),
       old_free_in_bytes);
   }
   return result;
 }
 void PSAdaptiveSizePolicy::clear_generation_free_space_flags() {
   AdaptiveSizePolicy::clear_generation_free_space_flags();
   set_change_old_gen_for_min_pauses(0);
   set_change_young_gen_for_maj_pauses(0);
 }
 // If this is not a full GC, only test and modify the young generation.
 void PSAdaptiveSizePolicy::compute_generation_free_space(
                                            size_t young_live,
                                            size_t eden_live,
                                            size_t old_live,
                                            size_t perm_live,
                                            size_t cur_eden,
                                            size_t max_old_gen_size,
                                            size_t max_eden_size,
                                            bool   is_full_gc,
                                            GCCause::Cause gc_cause,
                                            CollectorPolicy* collector_policy) {
   // Update statistics
   // Time statistics are updated as we go, update footprint stats here
   _avg_base_footprint->sample(BaseFootPrintEstimate + perm_live);
   avg_young_live()->sample(young_live);
   avg_eden_live()->sample(eden_live);
   if (is_full_gc) {
     // old_live is only accurate after a full gc
     avg_old_live()->sample(old_live);
   }
   // This code used to return if the policy was not ready , i.e.,
   // policy_is_ready() returning false.  The intent was that
   // decisions below needed major collection times and so could
   // not be made before two major collections.  A consequence was
   // adjustments to the young generation were not done until after
   // two major collections even if the minor collections times
   // exceeded the requested goals.  Now let the young generation
   // adjust for the minor collection times.  Major collection times
   // will be zero for the first collection and will naturally be
   // ignored.  Tenured generation adjustments are only made at the
   // full collections so until the second major collection has
   // been reached, no tenured generation adjustments will be made.
   // Until we know better, desired promotion size uses the last calculation
   size_t desired_promo_size = _promo_size;
   // Start eden at the current value.  The desired value that is stored
   // in _eden_size is not bounded by constraints of the heap and can
   // run away.
   //
   // As expected setting desired_eden_size to the current
   // value of desired_eden_size as a starting point
   // caused desired_eden_size to grow way too large and caused
   // an overflow down stream.  It may have improved performance in
   // some case but is dangerous.
   size_t desired_eden_size = cur_eden;
 #ifdef ASSERT
   size_t original_promo_size = desired_promo_size;
   size_t original_eden_size = desired_eden_size;
 #endif
   // Cache some values. There's a bit of work getting these, so
   // we might save a little time.
   const double major_cost = major_gc_cost();
   const double minor_cost = minor_gc_cost();
   // Used for diagnostics
   clear_generation_free_space_flags();
   // Limits on our growth
   size_t promo_limit = (size_t)(max_old_gen_size - avg_old_live()->average());
   // This method sets the desired eden size.  That plus the
   // desired survivor space sizes sets the desired young generation
   // size.  This methods does not know what the desired survivor
   // size is but expects that other policy will attempt to make
   // the survivor sizes compatible with the live data in the
   // young generation.  This limit is an estimate of the space left
   // in the young generation after the survivor spaces have been
   // subtracted out.
   size_t eden_limit = max_eden_size;
   // But don't force a promo size below the current promo size. Otherwise,
   // the promo size will shrink for no good reason.
   promo_limit = MAX2(promo_limit, _promo_size);
   const double gc_cost_limit = GCTimeLimit/100.0;
   // Which way should we go?
   // if pause requirement is not met
   //   adjust size of any generation with average paus exceeding
   //   the pause limit.  Adjust one pause at a time (the larger)
   //   and only make adjustments for the major pause at full collections.
   // else if throughput requirement not met
   //   adjust the size of the generation with larger gc time.  Only
   //   adjust one generation at a time.
   // else
   //   adjust down the total heap size.  Adjust down the larger of the
   //   generations.
   // Add some checks for a threshhold for a change.  For example,
   // a change less than the necessary alignment is probably not worth
   // attempting.
   if ((_avg_minor_pause->padded_average() > gc_pause_goal_sec()) ||
       (_avg_major_pause->padded_average() > gc_pause_goal_sec())) {
     //
     // Check pauses
     //
     // Make changes only to affect one of the pauses (the larger)
     // at a time.
     adjust_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
   } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
     // Adjust only for the minor pause time goal
     adjust_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
   } else if(adjusted_mutator_cost() < _throughput_goal) {
     // This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
     // This sometimes resulted in skipping to the minimize footprint
     // code.  Change this to try and reduce GC time if mutator time is
     // negative for whatever reason.  Or for future consideration,
     // bail out of the code if mutator time is negative.
     //
     // Throughput
     //
     assert(major_cost >= 0.0, "major cost is < 0.0");
     assert(minor_cost >= 0.0, "minor cost is < 0.0");
     // Try to reduce the GC times.
     adjust_for_throughput(is_full_gc, &desired_promo_size, &desired_eden_size);
   } else {
     // Be conservative about reducing the footprint.
     //   Do a minimum number of major collections first.
     //   Have reasonable averages for major and minor collections costs.
     if (UseAdaptiveSizePolicyFootprintGoal &&
         young_gen_policy_is_ready() &&
         avg_major_gc_cost()->average() >= 0.0 &&
         avg_minor_gc_cost()->average() >= 0.0) {
       size_t desired_sum = desired_eden_size + desired_promo_size;
       desired_eden_size = adjust_eden_for_footprint(desired_eden_size,
                                                     desired_sum);
       if (is_full_gc) {
         set_decide_at_full_gc(decide_at_full_gc_true);
         desired_promo_size = adjust_promo_for_footprint(desired_promo_size,
                                                         desired_sum);
       }
     }
   }
   // Note we make the same tests as in the code block below;  the code
   // seems a little easier to read with the printing in another block.
   if (PrintAdaptiveSizePolicy) {
     if (desired_promo_size > promo_limit)  {
       // "free_in_old_gen" was the original value for used for promo_limit
       size_t free_in_old_gen = (size_t)(max_old_gen_size - avg_old_live()->average());
       gclog_or_tty->print_cr(
             "PSAdaptiveSizePolicy::compute_generation_free_space limits:"
             " desired_promo_size: " SIZE_FORMAT
             " promo_limit: " SIZE_FORMAT
             " free_in_old_gen: " SIZE_FORMAT
             " max_old_gen_size: " SIZE_FORMAT
             " avg_old_live: " SIZE_FORMAT,
             desired_promo_size, promo_limit, free_in_old_gen,
             max_old_gen_size, (size_t) avg_old_live()->average());
     }
     if (desired_eden_size > eden_limit) {
       gclog_or_tty->print_cr(
             "AdaptiveSizePolicy::compute_generation_free_space limits:"
             " desired_eden_size: " SIZE_FORMAT
             " old_eden_size: " SIZE_FORMAT
             " eden_limit: " SIZE_FORMAT
             " cur_eden: " SIZE_FORMAT
             " max_eden_size: " SIZE_FORMAT
             " avg_young_live: " SIZE_FORMAT,
             desired_eden_size, _eden_size, eden_limit, cur_eden,
             max_eden_size, (size_t)avg_young_live()->average());
     }
     if (gc_cost() > gc_cost_limit) {
       gclog_or_tty->print_cr(
             "AdaptiveSizePolicy::compute_generation_free_space: gc time limit"
             " gc_cost: %f "
             " GCTimeLimit: %d",
             gc_cost(), GCTimeLimit);
     }
   }
   // Align everything and make a final limit check
   const size_t alignment = _intra_generation_alignment;
   desired_eden_size  = align_size_up(desired_eden_size, alignment);
   desired_eden_size  = MAX2(desired_eden_size, alignment);
   desired_promo_size = align_size_up(desired_promo_size, alignment);
   desired_promo_size = MAX2(desired_promo_size, alignment);
   eden_limit  = align_size_down(eden_limit, alignment);
   promo_limit = align_size_down(promo_limit, alignment);
   // Is too much time being spent in GC?
   //   Is the heap trying to grow beyond it's limits?
   const size_t free_in_old_gen =
     (size_t)(max_old_gen_size - avg_old_live()->average());
   if (desired_promo_size > free_in_old_gen && desired_eden_size > eden_limit) {
     check_gc_overhead_limit(young_live,
                             eden_live,
                             max_old_gen_size,
                             max_eden_size,
                             is_full_gc,
                             gc_cause,
                             collector_policy);
   }
   // And one last limit check, now that we've aligned things.
   if (desired_eden_size > eden_limit) {
     // If the policy says to get a larger eden but
     // is hitting the limit, don't decrease eden.
     // This can lead to a general drifting down of the
     // eden size.  Let the tenuring calculation push more
     // into the old gen.
     desired_eden_size = MAX2(eden_limit, cur_eden);
   }
   desired_promo_size = MIN2(desired_promo_size, promo_limit);
   if (PrintAdaptiveSizePolicy) {
     // Timing stats
     gclog_or_tty->print(
                "PSAdaptiveSizePolicy::compute_generation_free_space: costs"
                " minor_time: %f"
                " major_cost: %f"
                " mutator_cost: %f"
                " throughput_goal: %f",
                minor_gc_cost(), major_gc_cost(), mutator_cost(),
                _throughput_goal);
     // We give more details if Verbose is set
     if (Verbose) {
       gclog_or_tty->print( " minor_pause: %f"
                   " major_pause: %f"
                   " minor_interval: %f"
                   " major_interval: %f"
                   " pause_goal: %f",
                   _avg_minor_pause->padded_average(),
                   _avg_major_pause->padded_average(),
                   _avg_minor_interval->average(),
                   _avg_major_interval->average(),
                   gc_pause_goal_sec());
     }
     // Footprint stats
     gclog_or_tty->print( " live_space: " SIZE_FORMAT
                 " free_space: " SIZE_FORMAT,
                 live_space(), free_space());
     // More detail
     if (Verbose) {
       gclog_or_tty->print( " base_footprint: " SIZE_FORMAT
                   " avg_young_live: " SIZE_FORMAT
                   " avg_old_live: " SIZE_FORMAT,
                   (size_t)_avg_base_footprint->average(),
                   (size_t)avg_young_live()->average(),
                   (size_t)avg_old_live()->average());
     }
     // And finally, our old and new sizes.
     gclog_or_tty->print(" old_promo_size: " SIZE_FORMAT
                " old_eden_size: " SIZE_FORMAT
                " desired_promo_size: " SIZE_FORMAT
                " desired_eden_size: " SIZE_FORMAT,
                _promo_size, _eden_size,
                desired_promo_size, desired_eden_size);
     gclog_or_tty->cr();
   }
   decay_supplemental_growth(is_full_gc);
   set_promo_size(desired_promo_size);
   set_eden_size(desired_eden_size);
 };
 void PSAdaptiveSizePolicy::decay_supplemental_growth(bool is_full_gc) {
   // Decay the supplemental increment?  Decay the supplement growth
   // factor even if it is not used.  It is only meant to give a boost
   // to the initial growth and if it is not used, then it was not
   // needed.
   if (is_full_gc) {
     // Don't wait for the threshold value for the major collections.  If
     // here, the supplemental growth term was used and should decay.
     if ((_avg_major_pause->count() % TenuredGenerationSizeSupplementDecay)
         == 0) {
       _old_gen_size_increment_supplement =
         _old_gen_size_increment_supplement >> 1;
     }
   } else {
     if ((_avg_minor_pause->count() >= AdaptiveSizePolicyReadyThreshold) &&
         (_avg_minor_pause->count() % YoungGenerationSizeSupplementDecay) == 0) {
       _young_gen_size_increment_supplement =
         _young_gen_size_increment_supplement >> 1;
     }
   }
 }
 void PSAdaptiveSizePolicy::adjust_for_minor_pause_time(bool is_full_gc,
     size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
   // Adjust the young generation size to reduce pause time of
   // of collections.
   //
   // The AdaptiveSizePolicyInitializingSteps test is not used
   // here.  It has not seemed to be needed but perhaps should
   // be added for consistency.
   if (minor_pause_young_estimator()->decrement_will_decrease()) {
         // reduce eden size
     set_change_young_gen_for_min_pauses(
           decrease_young_gen_for_min_pauses_true);
     *desired_eden_size_ptr = *desired_eden_size_ptr -
       eden_decrement_aligned_down(*desired_eden_size_ptr);
     } else {
       // EXPERIMENTAL ADJUSTMENT
       // Only record that the estimator indicated such an action.
       // *desired_eden_size_ptr = *desired_eden_size_ptr + eden_heap_delta;
       set_change_young_gen_for_min_pauses(
           increase_young_gen_for_min_pauses_true);
   }
   if (PSAdjustTenuredGenForMinorPause) {
     // If the desired eden size is as small as it will get,
     // try to adjust the old gen size.
     if (*desired_eden_size_ptr <= _intra_generation_alignment) {
       // Vary the old gen size to reduce the young gen pause.  This
       // may not be a good idea.  This is just a test.
       if (minor_pause_old_estimator()->decrement_will_decrease()) {
         set_change_old_gen_for_min_pauses(
           decrease_old_gen_for_min_pauses_true);
         *desired_promo_size_ptr =
           _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
       } else {
         set_change_old_gen_for_min_pauses(
           increase_old_gen_for_min_pauses_true);
         size_t promo_heap_delta =
           promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
         if ((*desired_promo_size_ptr + promo_heap_delta) >
             *desired_promo_size_ptr) {
           *desired_promo_size_ptr =
             _promo_size + promo_heap_delta;
         }
       }
     }
   }
 }
 void PSAdaptiveSizePolicy::adjust_for_pause_time(bool is_full_gc,
                                              size_t* desired_promo_size_ptr,
                                              size_t* desired_eden_size_ptr) {
   size_t promo_heap_delta = 0;
   size_t eden_heap_delta = 0;
   // Add some checks for a threshhold for a change.  For example,
   // a change less than the required alignment is probably not worth
   // attempting.
   if (is_full_gc) {
     set_decide_at_full_gc(decide_at_full_gc_true);
   }
   if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
     adjust_for_minor_pause_time(is_full_gc,
                                 desired_promo_size_ptr,
                                 desired_eden_size_ptr);
     // major pause adjustments
   } else if (is_full_gc) {
     // Adjust for the major pause time only at full gc's because the
     // affects of a change can only be seen at full gc's.
     // Reduce old generation size to reduce pause?
     if (major_pause_old_estimator()->decrement_will_decrease()) {
       // reduce old generation size
       set_change_old_gen_for_maj_pauses(decrease_old_gen_for_maj_pauses_true);
       promo_heap_delta = promo_decrement_aligned_down(*desired_promo_size_ptr);
       *desired_promo_size_ptr = _promo_size - promo_heap_delta;
     } else {
       // EXPERIMENTAL ADJUSTMENT
       // Only record that the estimator indicated such an action.
       // *desired_promo_size_ptr = _promo_size +
       //   promo_increment_aligned_up(*desired_promo_size_ptr);
       set_change_old_gen_for_maj_pauses(increase_old_gen_for_maj_pauses_true);
     }
     if (PSAdjustYoungGenForMajorPause) {
       // If the promo size is at the minimum (i.e., the old gen
       // size will not actually decrease), consider changing the
       // young gen size.
       if (*desired_promo_size_ptr < _intra_generation_alignment) {
         // If increasing the young generation will decrease the old gen
         // pause, do it.
         // During startup there is noise in the statistics for deciding
         // on whether to increase or decrease the young gen size.  For
         // some number of iterations, just try to increase the young
         // gen size if the major pause is too long to try and establish
         // good statistics for later decisions.
         if (major_pause_young_estimator()->increment_will_decrease() ||
           (_young_gen_change_for_major_pause_count
             <= AdaptiveSizePolicyInitializingSteps)) {
           set_change_young_gen_for_maj_pauses(
           increase_young_gen_for_maj_pauses_true);
           eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
           *desired_eden_size_ptr = _eden_size + eden_heap_delta;
           _young_gen_change_for_major_pause_count++;
         } else {
           // Record that decreasing the young gen size would decrease
           // the major pause
           set_change_young_gen_for_maj_pauses(
             decrease_young_gen_for_maj_pauses_true);
           eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
           *desired_eden_size_ptr = _eden_size - eden_heap_delta;
         }
       }
     }
   }
   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print_cr(
       "AdaptiveSizePolicy::compute_generation_free_space "
       "adjusting gen sizes for major pause (avg %f goal %f). "
       "desired_promo_size " SIZE_FORMAT "desired_eden_size "
        SIZE_FORMAT
       " promo delta " SIZE_FORMAT  " eden delta " SIZE_FORMAT,
       _avg_major_pause->average(), gc_pause_goal_sec(),
       *desired_promo_size_ptr, *desired_eden_size_ptr,
       promo_heap_delta, eden_heap_delta);
   }
 }
 void PSAdaptiveSizePolicy::adjust_for_throughput(bool is_full_gc,
                                              size_t* desired_promo_size_ptr,
                                              size_t* desired_eden_size_ptr) {
   // Add some checks for a threshhold for a change.  For example,
   // a change less than the required alignment is probably not worth
   // attempting.
   if (is_full_gc) {
     set_decide_at_full_gc(decide_at_full_gc_true);
   }
   if ((gc_cost() + mutator_cost()) == 0.0) {
     return;
   }
   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print("\nPSAdaptiveSizePolicy::adjust_for_throughput("
       "is_full: %d, promo: " SIZE_FORMAT ",  cur_eden: " SIZE_FORMAT "): ",
       is_full_gc, *desired_promo_size_ptr, *desired_eden_size_ptr);
     gclog_or_tty->print_cr("mutator_cost %f  major_gc_cost %f "
       "minor_gc_cost %f", mutator_cost(), major_gc_cost(), minor_gc_cost());
   }
   // Tenured generation
   if (is_full_gc) {
     // Calculate the change to use for the tenured gen.
     size_t scaled_promo_heap_delta = 0;
     // Can the increment to the generation be scaled?
     if (gc_cost() >= 0.0 && major_gc_cost() >= 0.0) {
       size_t promo_heap_delta =
         promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
       double scale_by_ratio = major_gc_cost() / gc_cost();
       scaled_promo_heap_delta =
         (size_t) (scale_by_ratio * (double) promo_heap_delta);
       if (PrintAdaptiveSizePolicy && Verbose) {
         gclog_or_tty->print_cr(
           "Scaled tenured increment: " SIZE_FORMAT " by %f down to "
           SIZE_FORMAT,
           promo_heap_delta, scale_by_ratio, scaled_promo_heap_delta);
       }
     } else if (major_gc_cost() >= 0.0) {
       // Scaling is not going to work.  If the major gc time is the
       // larger, give it a full increment.
       if (major_gc_cost() >= minor_gc_cost()) {
         scaled_promo_heap_delta =
           promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
       }
     } else {
       // Don't expect to get here but it's ok if it does
       // in the product build since the delta will be 0
       // and nothing will change.
       assert(false, "Unexpected value for gc costs");
     }
     switch (AdaptiveSizeThroughPutPolicy) {
       case 1:
         // Early in the run the statistics might not be good.  Until
         // a specific number of collections have been, use the heuristic
         // that a larger generation size means lower collection costs.
         if (major_collection_estimator()->increment_will_decrease() ||
            (_old_gen_change_for_major_throughput
             <= AdaptiveSizePolicyInitializingSteps)) {
           // Increase tenured generation size to reduce major collection cost
           if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
               *desired_promo_size_ptr) {
             *desired_promo_size_ptr = _promo_size + scaled_promo_heap_delta;
           }
           set_change_old_gen_for_throughput(
               increase_old_gen_for_throughput_true);
               _old_gen_change_for_major_throughput++;
         } else {
           // EXPERIMENTAL ADJUSTMENT
           // Record that decreasing the old gen size would decrease
           // the major collection cost but don't do it.
           // *desired_promo_size_ptr = _promo_size -
           //   promo_decrement_aligned_down(*desired_promo_size_ptr);
           set_change_old_gen_for_throughput(
                 decrease_old_gen_for_throughput_true);
         }
         break;
       default:
         // Simplest strategy
         if ((*desired_promo_size_ptr + scaled_promo_heap_delta) >
             *desired_promo_size_ptr) {
           *desired_promo_size_ptr = *desired_promo_size_ptr +
             scaled_promo_heap_delta;
         }
         set_change_old_gen_for_throughput(
           increase_old_gen_for_throughput_true);
         _old_gen_change_for_major_throughput++;
     }
     if (PrintAdaptiveSizePolicy && Verbose) {
       gclog_or_tty->print_cr(
           "adjusting tenured gen for throughput (avg %f goal %f). "
           "desired_promo_size " SIZE_FORMAT " promo_delta " SIZE_FORMAT ,
           mutator_cost(), _throughput_goal,
           *desired_promo_size_ptr, scaled_promo_heap_delta);
     }
   }
   // Young generation
   size_t scaled_eden_heap_delta = 0;
   // Can the increment to the generation be scaled?
   if (gc_cost() >= 0.0 && minor_gc_cost() >= 0.0) {
     size_t eden_heap_delta =
       eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
     double scale_by_ratio = minor_gc_cost() / gc_cost();
     assert(scale_by_ratio <= 1.0 && scale_by_ratio >= 0.0, "Scaling is wrong");
     scaled_eden_heap_delta =
       (size_t) (scale_by_ratio * (double) eden_heap_delta);
     if (PrintAdaptiveSizePolicy && Verbose) {
       gclog_or_tty->print_cr(
         "Scaled eden increment: " SIZE_FORMAT " by %f down to "
         SIZE_FORMAT,
         eden_heap_delta, scale_by_ratio, scaled_eden_heap_delta);
     }
   } else if (minor_gc_cost() >= 0.0) {
     // Scaling is not going to work.  If the minor gc time is the
     // larger, give it a full increment.
     if (minor_gc_cost() > major_gc_cost()) {
       scaled_eden_heap_delta =
         eden_increment_with_supplement_aligned_up(*desired_eden_size_ptr);
     }
   } else {
     // Don't expect to get here but it's ok if it does
     // in the product build since the delta will be 0
     // and nothing will change.
     assert(false, "Unexpected value for gc costs");
   }
   // Use a heuristic for some number of collections to give
   // the averages time to settle down.
   switch (AdaptiveSizeThroughPutPolicy) {
     case 1:
       if (minor_collection_estimator()->increment_will_decrease() ||
         (_young_gen_change_for_minor_throughput
           <= AdaptiveSizePolicyInitializingSteps)) {
         // Expand young generation size to reduce frequency of
         // of collections.
         if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
             *desired_eden_size_ptr) {
           *desired_eden_size_ptr =
             *desired_eden_size_ptr + scaled_eden_heap_delta;
         }
         set_change_young_gen_for_throughput(
           increase_young_gen_for_througput_true);
         _young_gen_change_for_minor_throughput++;
       } else {
         // EXPERIMENTAL ADJUSTMENT
         // Record that decreasing the young gen size would decrease
         // the minor collection cost but don't do it.
         // *desired_eden_size_ptr = _eden_size -
         //   eden_decrement_aligned_down(*desired_eden_size_ptr);
         set_change_young_gen_for_throughput(
           decrease_young_gen_for_througput_true);
       }
           break;
     default:
       if ((*desired_eden_size_ptr + scaled_eden_heap_delta) >
           *desired_eden_size_ptr) {
         *desired_eden_size_ptr =
           *desired_eden_size_ptr + scaled_eden_heap_delta;
       }
       set_change_young_gen_for_throughput(
         increase_young_gen_for_througput_true);
       _young_gen_change_for_minor_throughput++;
   }
   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print_cr(
         "adjusting eden for throughput (avg %f goal %f). desired_eden_size "
         SIZE_FORMAT " eden delta " SIZE_FORMAT "\n",
       mutator_cost(), _throughput_goal,
         *desired_eden_size_ptr, scaled_eden_heap_delta);
   }
 }
 size_t PSAdaptiveSizePolicy::adjust_promo_for_footprint(
     size_t desired_promo_size, size_t desired_sum) {
   assert(desired_promo_size <= desired_sum, "Inconsistent parameters");
   set_decrease_for_footprint(decrease_old_gen_for_footprint_true);
   size_t change = promo_decrement(desired_promo_size);
   change = scale_down(change, desired_promo_size, desired_sum);
   size_t reduced_size = desired_promo_size - change;
   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print_cr(
       "AdaptiveSizePolicy::compute_generation_free_space "
       "adjusting tenured gen for footprint. "
       "starting promo size " SIZE_FORMAT
       " reduced promo size " SIZE_FORMAT,
       " promo delta " SIZE_FORMAT,
       desired_promo_size, reduced_size, change );
   }
   assert(reduced_size <= desired_promo_size, "Inconsistent result");
   return reduced_size;
 }
 size_t PSAdaptiveSizePolicy::adjust_eden_for_footprint(
   size_t desired_eden_size, size_t desired_sum) {
   assert(desired_eden_size <= desired_sum, "Inconsistent parameters");
   set_decrease_for_footprint(decrease_young_gen_for_footprint_true);
   size_t change = eden_decrement(desired_eden_size);
   change = scale_down(change, desired_eden_size, desired_sum);
   size_t reduced_size = desired_eden_size - change;
   if (PrintAdaptiveSizePolicy && Verbose) {
     gclog_or_tty->print_cr(
       "AdaptiveSizePolicy::compute_generation_free_space "
       "adjusting eden for footprint. "
       " starting eden size " SIZE_FORMAT
       " reduced eden size " SIZE_FORMAT
       " eden delta " SIZE_FORMAT,
       desired_eden_size, reduced_size, change);
   }
   assert(reduced_size <= desired_eden_size, "Inconsistent result");
   return reduced_size;
 }
 // Scale down "change" by the factor
 //      part / total
 // Don't align the results.
 size_t PSAdaptiveSizePolicy::scale_down(size_t change,
                                         double part,
                                         double total) {
   assert(part <= total, "Inconsistent input");
   size_t reduced_change = change;
   if (total > 0) {
     double fraction =  part / total;
     reduced_change = (size_t) (fraction * (double) change);
   }
   assert(reduced_change <= change, "Inconsistent result");
   return reduced_change;
 }
 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden,
                                             uint percent_change) {
   size_t eden_heap_delta;
   eden_heap_delta = cur_eden / 100 * percent_change;
   return eden_heap_delta;
 }
 size_t PSAdaptiveSizePolicy::eden_increment(size_t cur_eden) {
   return eden_increment(cur_eden, YoungGenerationSizeIncrement);
 }
 size_t PSAdaptiveSizePolicy::eden_increment_aligned_up(size_t cur_eden) {
   size_t result = eden_increment(cur_eden, YoungGenerationSizeIncrement);
   return align_size_up(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::eden_increment_aligned_down(size_t cur_eden) {
   size_t result = eden_increment(cur_eden);
   return align_size_down(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::eden_increment_with_supplement_aligned_up(
   size_t cur_eden) {
   size_t result = eden_increment(cur_eden,
     YoungGenerationSizeIncrement + _young_gen_size_increment_supplement);
   return align_size_up(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::eden_decrement_aligned_down(size_t cur_eden) {
   size_t eden_heap_delta = eden_decrement(cur_eden);
   return align_size_down(eden_heap_delta, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::eden_decrement(size_t cur_eden) {
   size_t eden_heap_delta = eden_increment(cur_eden) /
     AdaptiveSizeDecrementScaleFactor;
   return eden_heap_delta;
 }
 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo,
                                              uint percent_change) {
   size_t promo_heap_delta;
   promo_heap_delta = cur_promo / 100 * percent_change;
   return promo_heap_delta;
 }
 size_t PSAdaptiveSizePolicy::promo_increment(size_t cur_promo) {
   return promo_increment(cur_promo, TenuredGenerationSizeIncrement);
 }
 size_t PSAdaptiveSizePolicy::promo_increment_aligned_up(size_t cur_promo) {
   size_t result =  promo_increment(cur_promo, TenuredGenerationSizeIncrement);
   return align_size_up(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::promo_increment_aligned_down(size_t cur_promo) {
   size_t result =  promo_increment(cur_promo, TenuredGenerationSizeIncrement);
   return align_size_down(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::promo_increment_with_supplement_aligned_up(
   size_t cur_promo) {
   size_t result =  promo_increment(cur_promo,
     TenuredGenerationSizeIncrement + _old_gen_size_increment_supplement);
   return align_size_up(result, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::promo_decrement_aligned_down(size_t cur_promo) {
   size_t promo_heap_delta = promo_decrement(cur_promo);
   return align_size_down(promo_heap_delta, _intra_generation_alignment);
 }
 size_t PSAdaptiveSizePolicy::promo_decrement(size_t cur_promo) {
   size_t promo_heap_delta = promo_increment(cur_promo);
   promo_heap_delta = promo_heap_delta / AdaptiveSizeDecrementScaleFactor;
   return promo_heap_delta;
 }
 int PSAdaptiveSizePolicy::compute_survivor_space_size_and_threshold(
                                              bool is_survivor_overflow,
                                              int tenuring_threshold,
                                              size_t survivor_limit) {
   assert(survivor_limit >= _intra_generation_alignment,
          "survivor_limit too small");
   assert((size_t)align_size_down(survivor_limit, _intra_generation_alignment)
          == survivor_limit, "survivor_limit not aligned");
   // This method is called even if the tenuring threshold and survivor
   // spaces are not adjusted so that the averages are sampled above.
   if (!UsePSAdaptiveSurvivorSizePolicy ||
       !young_gen_policy_is_ready()) {
     return tenuring_threshold;
   }
   // We'll decide whether to increase or decrease the tenuring
   // threshold based partly on the newly computed survivor size
   // (if we hit the maximum limit allowed, we'll always choose to
   // decrement the threshold).
   bool incr_tenuring_threshold = false;
   bool decr_tenuring_threshold = false;
   set_decrement_tenuring_threshold_for_gc_cost(false);
   set_increment_tenuring_threshold_for_gc_cost(false);
   set_decrement_tenuring_threshold_for_survivor_limit(false);
   if (!is_survivor_overflow) {
     // Keep running averages on how much survived
     // We use the tenuring threshold to equalize the cost of major
     // and minor collections.
     // ThresholdTolerance is used to indicate how sensitive the
     // tenuring threshold is to differences in cost betweent the
     // collection types.
     // Get the times of interest. This involves a little work, so
     // we cache the values here.
     const double major_cost = major_gc_cost();
     const double minor_cost = minor_gc_cost();
     if (minor_cost > major_cost * _threshold_tolerance_percent) {
       // Minor times are getting too long;  lower the threshold so
       // less survives and more is promoted.
       decr_tenuring_threshold = true;
       set_decrement_tenuring_threshold_for_gc_cost(true);
     } else if (major_cost > minor_cost * _threshold_tolerance_percent) {
       // Major times are too long, so we want less promotion.
       incr_tenuring_threshold = true;
       set_increment_tenuring_threshold_for_gc_cost(true);
     }
   } else {
     // Survivor space overflow occurred, so promoted and survived are
     // not accurate. We'll make our best guess by combining survived
     // and promoted and count them as survivors.
     //
     // We'll lower the tenuring threshold to see if we can correct
     // things. Also, set the survivor size conservatively. We're
     // trying to avoid many overflows from occurring if defnew size
     // is just too small.
     decr_tenuring_threshold = true;
   }
   // The padded average also maintains a deviation from the average;
   // we use this to see how good of an estimate we have of what survived.
   // We're trying to pad the survivor size as little as possible without
   // overflowing the survivor spaces.
   size_t target_size = align_size_up((size_t)_avg_survived->padded_average(),
                                      _intra_generation_alignment);
   target_size = MAX2(target_size, _intra_generation_alignment);
   if (target_size > survivor_limit) {
     // Target size is bigger than we can handle. Let's also reduce
     // the tenuring threshold.
     target_size = survivor_limit;
     decr_tenuring_threshold = true;
     set_decrement_tenuring_threshold_for_survivor_limit(true);
   }
   // Finally, increment or decrement the tenuring threshold, as decided above.
   // We test for decrementing first, as we might have hit the target size
   // limit.
   if (decr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
     if (tenuring_threshold > 1) {
       tenuring_threshold--;
     }
   } else if (incr_tenuring_threshold && !(AlwaysTenure || NeverTenure)) {
     if (tenuring_threshold < MaxTenuringThreshold) {
       tenuring_threshold++;
     }
   }
   // We keep a running average of the amount promoted which is used
   // to decide when we should collect the old generation (when
   // the amount of old gen free space is less than what we expect to
   // promote).
   if (PrintAdaptiveSizePolicy) {
     // A little more detail if Verbose is on
     if (Verbose) {
       gclog_or_tty->print( "  avg_survived: %f"
                   "  avg_deviation: %f",
                   _avg_survived->average(),
                   _avg_survived->deviation());
     }
     gclog_or_tty->print( "  avg_survived_padded_avg: %f",
                 _avg_survived->padded_average());
     if (Verbose) {
       gclog_or_tty->print( "  avg_promoted_avg: %f"
                   "  avg_promoted_dev: %f",
                   avg_promoted()->average(),
                   avg_promoted()->deviation());
     }
     gclog_or_tty->print( "  avg_promoted_padded_avg: %f"
                 "  avg_pretenured_padded_avg: %f"
                 "  tenuring_thresh: %d"
                 "  target_size: " SIZE_FORMAT,
                 avg_promoted()->padded_average(),
                 _avg_pretenured->padded_average(),
                 tenuring_threshold, target_size);
     tty->cr();
   }
   set_survivor_size(target_size);
   return tenuring_threshold;
 }
 void PSAdaptiveSizePolicy::update_averages(bool is_survivor_overflow,
                                            size_t survived,
                                            size_t promoted) {
   // Update averages
   if (!is_survivor_overflow) {
     // Keep running averages on how much survived
     _avg_survived->sample(survived);
   } else {
     size_t survived_guess = survived + promoted;
     _avg_survived->sample(survived_guess);
   }
   avg_promoted()->sample(promoted + _avg_pretenured->padded_average());
   if (PrintAdaptiveSizePolicy) {
     gclog_or_tty->print(
                   "AdaptiveSizePolicy::compute_survivor_space_size_and_thresh:"
                   "  survived: "  SIZE_FORMAT
                   "  promoted: "  SIZE_FORMAT
                   "  overflow: %s",
                   survived, promoted, is_survivor_overflow ? "true" : "false");
   }
 }
 bool PSAdaptiveSizePolicy::print_adaptive_size_policy_on(outputStream* st)
   const {
   if (!UseAdaptiveSizePolicy) return false;
   return AdaptiveSizePolicy::print_adaptive_size_policy_on(
                           st,
                           PSScavenge::tenuring_threshold());
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp@8a729074feae (annotated)

src/share/vm/gc_implementation/parallelScavenge/psAdaptiveSizePolicy.cpp